In order to ensure total secrecy on a set, it's common enough for directors and producers to try numerous measures to keep things locked down from people like us.

For one, major movies tend to having working titles or codenames that throw journalists and the public off the scent. It also ensures that local businesses don't massively overcharge production companies when they know the name of the movie franchise, too.

Christopher Nolan, however, laughs in the face of this secrecy and scoffs at your weak-willed attempts at plot secrecy. The most recent victim of Nolan's utter secrecy on set has been none other than his trusty compatriot, Michael Caine.

When asked about plot details on his latest effort with Nolan, the octogenarian - who turns 87 today, in fact - explained the director's process and why he hasn't got a clue what 'Tenet' is about. "All I had was one day’s work and he gave me my pages,” the actor explained to The Hindu in a recent interview. “I did my part and shot only with John David (Washington). I haven’t heard anything since."

In fairness, this wasn't exclusive to poor old Michael Caine either. Liam Neeson got the same treatment when he was brought back for 'The Dark Knight Rises' in a scene where he appeared as an apparition to Bruce Wayne in the prison where Bane left him.

At the time, Neeson was pretty miffed about only being given a page of dialogue, as he wanted to get back into character and have a broader understanding of his place in the story. To be fair to Nolan however, it was basically a cameo and he wasn't really in the story as such.

'Tenet' is scheduled (so far, anyway) for release in Irish cinemas on July 17th.